CSV ⇄ JSON Converter

Convert between CSV and JSON

CSV Input
1
JSON Output
1
Code Examples

CSV → JSON (using PapaParse)

const csvData = "name,age,city\nJohn Doe,28,New York\nJane Smith,32,Chicago";

const json = Papa.parse(csvData, {
  header: true,
  skipEmptyLines: true,
  dynamicTyping: true
}).data;

console.log(JSON.stringify(json, null, 2));

JSON → CSV (using PapaParse)

const data = [
  { name: "John Doe", age: 28, city: "New York" },
  { name: "Jane Smith", age: 32, city: "Chicago" }
];

const csv = Papa.unparse(data);
console.log(csv);
About CSV ⇄ JSON Converter

What is CSV ⇄ JSON Converter?

A CSV ⇄ JSON Converter is a tool that transforms data between CSV (Comma-Separated Values) and JSON (JavaScript Object Notation) formats. CSV is commonly used for tabular data in spreadsheets, while JSON is the standard format for APIs, web applications, and structured data.

Common Use Cases

  • Data Import/Export: Convert spreadsheet data to JSON for web applications
  • API Development: Transform CSV data into JSON for API responses
  • Database Migration: Convert CSV exports to JSON for NoSQL databases like MongoDB
  • Data Cleaning: Transform CSV to JSON for easier manipulation and validation
  • Analytics: Convert Google Sheets/Excel CSV to JSON for data analysis scripts
  • Backend Integration: Transform JSON API responses to CSV for reporting

How to Use

  1. Choose your conversion mode (CSV → JSON or JSON → CSV)
  2. Input your data by typing, pasting, or uploading a file
  3. Configure options like delimiter, headers, and formatting
  4. Click "Convert" or enable "Auto Convert" for live conversion
  5. Copy or download the converted output

Features

  • Bidirectional conversion (CSV ↔ JSON)
  • Multiple delimiter support (comma, semicolon, pipe, tab)
  • Header row detection and toggling
  • Auto-detect data types (numbers, booleans)
  • Pretty print JSON output
  • Flatten nested JSON objects for CSV
  • File upload support (.csv and .json)
  • Live conversion mode
  • Error detection and helpful messages
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About This Tool

CSV to JSON conversion is something I do constantly when integrating data between spreadsheets, databases, and APIs. Excel exports, database dumps, and analytics reports often come as CSV, but modern web applications and APIs speak JSON. This tool bridges that gap instantly—paste CSV from Excel, Google Sheets, or database export, and get properly formatted JSON arrays of objects ready for API requests or JavaScript processing. It handles custom delimiters (commas, semicolons, tabs, pipes), quoted fields with embedded delimiters, and multi-line values. The reverse direction (JSON to CSV) is equally useful for creating spreadsheet-friendly data exports from API responses or converting NoSQL documents to tabular format for analysis in Excel or Tableau.

How to Use

Select conversion direction: CSV → JSON or JSON → CSV. For CSV input: paste your CSV data—first row should be column headers which become JSON object keys. Configure delimiter (comma, semicolon, tab, pipe, or custom), quote character (for fields containing delimiters), and whether first row contains headers. The tool parses CSV and outputs an array of JSON objects with automatic type detection (numbers, booleans, null). For JSON input: paste array of objects—keys become CSV column headers. Configure output options: delimiter choice, quote style (minimal, all fields, or non-numeric), and whether to include header row. The tool handles nested objects by flattening (e.g., user.name becomes 'user.name' column) or stringifying nested data. Download converted data or copy to clipboard.

Common Use Cases

Excel to API

Export customer data from Excel as CSV, convert to JSON, send to REST API with fetch() or curl for bulk import.

Database Export

Export PostgreSQL query results as CSV, convert to JSON for processing in JavaScript or Python data pipelines.

Analytics Integration

Download Google Analytics CSV report, convert to JSON, feed into custom dashboards or visualization tools.

Data Migration

Extract legacy database tables as CSV, convert to JSON, import into MongoDB or other NoSQL databases.

Testing Data

Create test fixtures by editing CSV in Excel (easy tabular editing), convert to JSON for Jest/Mocha test data.

API Response to Spreadsheet

Fetch JSON from API, convert to CSV, import into Excel for non-technical stakeholders to analyze.

Limitations & Important Notes

Very large CSV files (>50MB) may cause browser memory issues—use command-line tools like csvkit or pandas for huge datasets. The tool assumes UTF-8 encoding—other encodings (Latin-1, Windows-1252) may display incorrectly. Complex nested JSON (deeply nested objects, mixed arrays) doesn't convert cleanly to flat CSV—consider JSON flattening first. The CSV format lacks data types—all values are strings; JSON conversion guesses types (numbers, booleans) which may be wrong for IDs like '00123' (loses leading zero). Multi-line CSV values (quoted newlines) are supported but can be fragile—inspect carefully. The tool doesn't validate CSV schema—inconsistent column counts per row may produce unexpected results. For production ETL pipelines, use specialized tools (Apache NiFi, Airflow, Fivetran) with error handling and logging.